Rowing machine



FIG. 1 is a perspective view of a rowing machine showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view thereof, the side opposite being substantially a mirror image;

FIG. 4 is a front elevational view thereof; and,

FIG. 5 is a rear elevational view thereof. 

The ornamental design for a rowing machine, substantially as shown and described. 